In recent years, inorganic fine particle-dispersed paste compositions comprising electroconductive particles, ceramics, glass, a phosphor, or other inorganic fine particles dispersed in a binder resin have been used for obtaining sintered bodies of various shapes. For example, a paste composition comprising fine metal particles dispersed as electroconductive particles has been used in the formation of circuits etc. on a substrate; a glass paste comprising dispersed glass and a phosphor paste comprising dispersed phosphor have been used in the production of plasma display panels; and a ceramic paste comprising dispersed ceramics has been molded into a green sheet, and then used in the production of a multilayer ceramic capacitor or the like.
Conventionally, ethyl cellulose, polyvinyl butyral, poly(methyl methacrylate), and the like have been used as binder resins. For these binder resins, the dewaxing temperature for removal by thermal decomposition is as high as 300° C. or higher, and the residual carbon is in a large amount, so that enormous energy is required in the production of a molded article. Further, when inorganic fine particles are handled, particularly when particles subject to reaction with oxygen are handled, dewaxing is preferably performed in a non-oxidative atmosphere, in which case the temperature required for dewaxing would be even higher. In view of the above, a binder resin is desired for which dewaxing can be performed at a lower temperature even in a non-oxidative atmosphere, as in an oxidative atmosphere.
In order to meet such demands, studies have been conducted with respect to a polycarbonate resin produced from carbon dioxide and an epoxide for use as a low-temperature decomposable binder, since this polycarbonate resin has a decomposition temperature as low as 200 to 250° C. even in a non-oxidative atmosphere. For example, Patent Literature (PTL) 1 discloses a metal paste composition in which a polypropylene carbonate, which is one of the aliphatic polycarbonates, is used as a binder, and similarly, PTL 2 discloses a ceramic paste, and PTL 3 discloses a glass paste, respectively.